Weird, hairy microbes discovered on volcano soon after eruption

Gone today, hair tomorrow. Soon after an underwater volcano erupted and wiped out all nearby life forms, hardy bacteria moved in and covered the area in a huge mat of hair-like filaments.

These strange colonies were found by an expedition to Tagoro Volcano, near the Canary Islands, in 2014, two years after an eruption that reshaped 9 square kilometres of the sea floor. The researchers explored the area via a robotic submarine equipped with cameras and arms for collecting samples.

“Something very strange appeared to us: a very nice picturesque coverage of very long white filaments which were very unusual. It was the first time we had seen something like that,” says Roberto Danovaro of the Polytechnic University of Marche, Italy.

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They named the organism Venus’s hair, recalling Botticelli’s painting of the goddess Venus emerging from the sea.

Genetic analysis showed that it was very different from any other known microbes. Most striking, Danovaro says, were the huge portfolio of metabolic functions enabling the bacteria to grow in such a hostile environment. In particular, most organisms would be killed by the hydrogen sulphide coming out of the rocks, but instead it is an energy source for Venus’s hair, just like bacteria that grow around hydrothermal vents.

Opportunist bacteria

It’s not clear when the bacteria arrived, but Danovaro thinks they started colonising the area as soon as the temperature dropped. David Kirchman of the University of Delaware agrees. “I bet there were microbes appearing there just as soon as those rocks got below 100 oC,” he says.

Where did they come from, though? Unlike hydrothermal vents, this volcano was isolated, far from other habitats where you might expect to find similar microbes. “These organisms apparently come out of nowhere,” says Kirchman. He thinks the most likely explanation is that they are normally present in the water column but at very low levels.

“It’s helpful to remember that each drop of seawater contains millions of bacteria and that only one of them, in theory, is needed to colonise a new habitat,” says Kirchman. “The Venus’s hair bacterium could have been in this ‘rare biosphere’ and by chance came across the virgin habitat created by the volcanic eruption.”

Once the Venus’s hair bacteria colonised the area, creating a three-dimensional habitat, other organisms could move in, too. The expedition found small animals like crustaceans, worms and nematodes making their homes in the mat.

Danovaro thinks Venus’s hair may help us to imagine what life was like in the primordial ocean, where volcanic activity was common. “Possibly these organisms were able to do a lot of things because the variability of sources and environmental conditions was huge.”